Reshad, On Fri, Oct 26, 2018 at 06:32:26PM +0000, Reshad Rahman (rrahman) wrote: >On 2018-10-25, 11:38 AM, "Jeffrey Haas" <jh...@pfrc.org> wrote: > > The draft I had previously worked on with Xiao Min discussing probing > > using > > BFD Echo had the concept of probes that would happen wherein the > > session is > > not torn down. The example carries similarly with the "send > > occasional". > > <RR> We discussed use of echo at IETF102. The large-packets draft mentions > that echo can only be used for single-hop, hence the need for padding the > control packets. But isn't single-hop Albert's main use-case?
It's Albert's primary use case. And, I think a common related one is protecting tunnels of various flavors; e.g. GRE or IPsec. > I believe we > should add the echo option in the large-packets draft, it has the benefit > that you get the desired functionality even if only 1 side of the WAN link > supports echo. I realize not all implementations support echo so they > might have to do pad control packets instead. While I don't think Albert or I would have any objections to adding Echo discussion in the existing document, we perhaps risk running into one of the issues Xiao and I had briefly discussed. Echo is intentionally under-specified in RFC 5880 et seq. While it's possible that we can simply put in a discussion section that says "if you use Echo mode with similar padding, you can get similar benefit", I think that may be as far as we want to go. The related observation is that nothing stops an Echo implementation from doing this with no changes to the protocol. :-) -- Jeff
